Bulldozer



G. W. MORK Dec. 1, 1942.

BULLDOZER Filed Aug. '9, 1941 2 Sheets-Sheet l W a 1 4 4 a a 1 U Z 3 IQ4 2 F. 97 Q a 2 L. 7w W 7 h 2 6 3 2 my L 0 7N a: h Z 1 0 a w 7 [/1 9 a 9w w 4 INVENT OR.

ATTORNEYS.

G. W. MORK Dec. 1, 1942.

BULLDOZER Filed Aug. 9, 1941 2 Sheets-Sheet 2 ATTORNEYS Patented Dec. 1,1942 2,303,379 BULLDOZER George W. Mork, South Milwaukee, Wis., assignorto Bucyrus-Erie Company, South Milwaukee, Wis., a corporation oiDelaware Application August 9, 1941, Serial No. 406,091

Claims.

My invention relates to new and useful improvements in bulldozers, andmore particularly to that type of bulldozer in which the scrapingmoldboard is pushed ahead of a tractor.

Such devices are usually designed for attachment to some conventionaltype of tractor.

They consist of a moldboard, two arms pivoted tioned means usuallyconsists of one or two hydraulic cylinders actuated by a pump driven bythe engine of the tractor.

The moldboard is usually concave toward the front in verticalcross-section, the ends being closed by flat plates. But such animplement is adapted merely to push dirt along ahead of it, rather thanto carry the dirt. I

Accordingly it is the principal object of my invention to modify theconventional bulldozer so that it may carry dirt, as well as push it.

In addition to my principal object, above stated, I have worked out anumber of novel and useful details, which will be readily evident as thedescription progresses.

My invention consists in the novel parts and in the combination andarrangement thereof, which are defined in the appended claims, and ofwhich one embodiment is exemplified in the accompanying drawings, whichare hereinafter particularly described and explained.

Throughout thedescription the same reference number is applied to thesame member or to similar members.

Figure l is a plan view of a tractor and bulldozer embodying myinvention.

Figure 2 is a side elevation of this same tractor and bulldozer.

Figure 3 is an enlarged side elevation, partly in section, of themoldboard and associate parts of my invention, in pushing position;showing dotted these parts in carrying position.

Referring now to the figures, we see that H is a conventional tractor,mounted on creeping traction l2. These creeping traction elements arepivoted on propelling shaft l3, and their front ends have considerablefreedom to rise and fall to conforrn'to unevenness of the ground.

Pivotedto each traction element l2 at H is a forwardly'pr'ojecting arml5. These arms support and impel a moldboard I6.

On each side of the tractor there is a link I! pivoted to the rear ofthe tractor at I 8, and a These two links are pivoted together at 2|,and at this point is also pivoted the elbow of a bellcrank 22.

The front end of each bell-crank supports one side of the moldboard l6through a link 23.

There are two cylinders 24, each pivoted at on one of the links H. Thepiston rod 26 of each cylinder is pivoted at 21 to the short arm of thebell-crank 22.

The rear ends of the two cylinders are connected by a pipe 23, fromwhich a pipe 29 leads to a control-valve 30. The front ends of the twocylinders are similarly connected by a pipe 3|, from which a pipe 32leads to the control-valve 30. How this valve derives power from thepump and tank, hereinafter mentioned, forms no part of my presentinvention, and hence will not be described herein. y

We now come to the inventive features of my invention, on which seeprimarily Figure 3.

Below my moldboard I8, is a shoe 33, carrying a digging edge 34, bothrigidly secured to arms IS. The moldboard proper I! has each end closedby a plate 35, and is hinged to the shoe 33 in any convenient manner, asby a piano-hinge 38.

Along the back of the top of moldboard proper I6 is an angle beam orbracket 31, for resting engagement with rests 33. on each arm l5.

- On the back of the moldboard proper l6 are several verticalreinforcing ribs 39.

On each arm I5 is pivoted an hydraulic cylinder 40, the piston 4| ofwhich is pivoted to one .or more ribs 39. This cylinder 40 is preferablydouble-acting, pressure being provided by two pipes 42 and 43, extendingto a valve 44, from which valve a pressure pipe 45 and a return pipe 46extend to a pump 41, with appropriate connections 43 and 49 to a fluidtank 50.

My invention operates as follows. My digging edge 34 being lowered tothe ground b proper manipulation of cylinders 24, the tractor II ispropelled forwards, until a sizeable amount of dirt has piled up aheadof moldboard l6.

By proper manipulation of valve 44, fluid under pressure is admitted tothe front end of 0571- inders 40 through pipe 43, and fluid is permittedto withdraw from the rear end of cylinders 40 through pipe 42. Thisretracts piston 4|, causing the moldboard IE to lie back against rest33. Further forward motion of the tractor fills the moldboard with dirt.The load is prevented from spilling over the back end of the moldboardIt by guard plate 5| which is link l3 pivoted to the creeping tractionat 20. mounted on the arms l5 above and back of rests 38 and extendsfrom one arm -li to the other arm l5.

Cylinders 24 can then be manipulated to raise the moldboard and itsload, whereupon the load can be transported.

By reversing the valve 44 and the operation of the cylinders 40, theload can be dumped, the digging edge being lowered by cylinders 24, tospread the load.

Having now described and illustrated one form of my invention, I wish itto be understood that my invention is not to be limited to the specificform or arrangement or parts hereinbei'ore described except as specifiedin the appended claims.

I claim:

1. In a bulldozer, for attachment to a tractor, the combination a pair01' push-arms, pivotally attachable to the tractor; means, support ableby the tractor, for raising and lowering these arms; a transverse shoe,rigidly supported by the arms; a digging edge, rigidly carried by theshoe; a transverse moldboard, concave forwardly, hingedly connectedadjacent its lower edge to the shoe; vertical stifiening flanges on therear face of the moldboard; forwardly projecting plates, closing theends of the moldboard; a transverse rest bracket along the upper edge ofthe moldboard; a cooperating transverse rest carried rigidly by thearms; two double-acting cylinders, carried pivotally one by each arm,their pistons being pivotally connected to certain of the verticalstifienlng flanges on the moldboard; and means for introducing fiuidunder pressure to the cylinders, to swing the moldboard selectively toupright dirt-pushing position, or to recumbent dirt-carrying positionagainst the rest.

2. In a bulldozer, for attachment to a tractor, the combination of apair of push-arms, pivotally attachable to the tractor; means,supportable by the tractor, for raising and lowering moldboardselectively to upright dirt-pushing position, or to recumbentdirt-carrying position against the rest.

3. In a. bulldozer, for attachment to a tractor, the combination of: apair or push-arms, pivotally attachable to the tractor; means,supportable by the -tractor, for raising and lowering these arms;transverse digging means, rigidly carried by the arms, a transversemoldboard. hingedly carried by the arms; forcibly extendible andretractable means, extending between the arms and the moldboard; andmeans for selectively causing the last-mentioned 'means to extend orretract, to swing the moldboard selectively to upright dirt-pushingposition, or to recumbent dirt-carrying position.

4. In a bulldozer, for attachment to a tractor, the combination of: pushmeans, attachable to the tractor; means, supportable by the tractor, forraising and lowering the push means; transverse digging means, carriedby the push means; a transverse moldboard, separate and distinct fromthe digging means, and hingedly carried by the push means; andpower-operated means to swing the moldboard from recumbent dirtcarryingposition to upright dirt-pushing position.

5. A bulldozer, according to claim 2, characterized by the addition of atransverse guard plate, separately carried by the push-arms, and servingas a closure 01' the upper edge of the moldboard, when the latter is inrecumbent dirt-carrying position.

GEORGE W. MORK.

